In connection with storage tanks or volatile products, the requirements for eliminating any vapor emissions have been found difficult where the tank has a floating roof and includes a perforated gauge well. The perforated gauge well may give us better mixing in the well but comprises vapor emissions. Therefore unslotted wells are used but reduce the mixing effect.
The lack of vapor seal caused by the foregoing indicated structure is overcome by the use of a seal structure.
Gauge well systems are known in the art. The systems for a gauge well typically are used in a liquid storage tank with a floating roof. Unslotted gauge wells especially are known to cause tank-level measurement errors. Slotted gauge wells have provided somewhat of an improvement. Unslotted gauge wells give a false level readings in multi-use tanks due to gravity differences.